Endoscope with variable profile tip

ABSTRACT

A single-use electronic endoscope has a hub, a shaft extending from the hub, flexible or rigid as desired, and an expandable distal tip extending from the shaft. Within the distal tip, an image sensor provides a field of view external from the endoscope. Illuminating elements or light guides within the distal tip emit light to illuminate the field of view. The distal tip also has a variable profile working channel that permits tools to be passed from the hub and into the field of view. The expandable working channel changes cross-sectional shape from a generally noncircular shape to a shape to accommodate the cross-sectional shape of the tool when expanded.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The described technology relates generally to devices and methods forimaging within a body lumen, cavity or other enclosed space, and, moreparticularly, it relates to a single-use electronic endoscope forvarious uses (e.g., for arthroscopic knee surgery).

2. Description of the Related Art

Diagnosing and treating patients often involves examination of internalorgans and structures. In “open surgery,” a large surgical cut orincision is made in the patient's skin and flesh. Doing so permits thedoctor to see directly into and access the area being treated. However,large surgical wounds cause significant patient pain, involve use ofpowerful anesthetics and analgesics such as narcotics to keep thepatient comfortable during and after surgery, often take significanttime to heal and limit post-surgical patient activity (particularly ifmuscle is cut to access the treatment area).

To avoid disturbing nearby tissues, doctors use various imagingtechnologies to probe ducts, orifices, bodily openings, or other spaces.Such devices allow remote viewing of difficult-to-access spaces withoutlarge incisions, and have been referred to by different names, includingangioscope, arthroscope, borescope, cystoscope, endoscope, andfiberscope.

Arthroscopy is increasingly popular. Common arthroscopic proceduresexamine and treat damaged tissue within various body joints, such as byremoval or repair of torn cartilage portions of the meniscus, ligament,and tendon reconstruction, removal of loose debris, and trimming orshaving damaged articular cartilage. More than 4 million kneearthroscopies and more than 1.4 million shoulder arthroscopies areperformed worldwide each year, according to the American OrthopedicSociety for Sports Medicine. Other joints such as the shoulder, elbow,ankle, hip, and wrist can also be viewed through arthroscopy.

An endoscope has a light source and a camera. Fiberscopes (orfiber-optic endoscopes) include both illumination fibers or light guidesto direct light which illuminates the field of view and imaging fiberbundles to transfer the image of an illuminated area to the camera. Indiagnostic arthroscopy, after introducing the device into the patient'sjoint, the doctor shines light into that joint. The camera provides animage of the joint, which is then viewed on a video monitor. By viewingthe joint of interest through the device, the doctor does not need tomake a large incision. Sterile fluid can be used to expand the joint,which increases visibility in the joint area and makes it easier for thedoctor to work. These single-port diagnostic procedures have beenperformed in a doctor's office and “walk in” or ambulatory surgerycenters, e.g., using a 2.0 mm fiber optic arthroscope. Routinely thesediagnostic procedures are performed under local anesthetic to numb thearea being examined and the patient remains awake throughout theprocedure.

Other endoscopes are used to actively treat or operate on patients'joints. The doctor inserts the endoscope into the joint. Additionalholes or incisions can be provided to allow other tools to be usedduring the surgery to cut, shave, remove particles in the joint, orrepair tissue. Alternatively, the endoscope can include a workingchannel that allows surgical tools (e.g., biopsy forceps and othertools) to slide in and out of the joint.

Such operative or therapeutic arthroscopic surgery has limitations.Operative endoscopes with working channels for arthroscopy are typically3-4 mm in diameter. This makes the overall procedure more invasive andmore taxing on the patient than when smaller diagnostic endoscopes areused.

Operational arthroscopic procedures can have life-threatening risks.General anesthesia, with its attendant risks, can be used, particularlyfor more interventional operative arthroscopy. To avoid accidentalpatient infection, doctors use sterile techniques and equipment.

Such risks are not trivial. The Ronald Reagan UCLA Medical Center is aleader in performing the latest minimally invasive endoscopicprocedures. In February 2015, as many as 179 people at that hospitalwere exposed to drug-resistant bacteria while undergoing endoscopicprocedures. According to press reports, seven of those people becomeinfected with methicillin-resistant Staphylococcus aureus (MRSA), andtwo of those patients died.

The U.S. Food & Drug Administration issued a general warning to allhealth providers regarding the use of medical endoscopes for complexendoscopic procedures. The complex design of some endoscopes impedes theability to clean, disinfect, and sterilize these reusable devices.

Previously known endoscopes suffer a number of disadvantages, includingsignificant initial cost and the need for sterilization after each use.Such sterilization procedures are time consuming and lead to furtherexpense.

U.S. Pat. No. 6,840,909 to Gatto describes a device for removal oftissue and cells from breast ducts. At its distal end, the device has arigid or semi-rigid cannula tube. This cannula has an outer diameterranging from 0.5 mm to approximately 1.2 mm, and acts as a guide tubefor an endoscope. To obtain biopsy cells and tissue, a physicianmanipulates the cannula tube itself to scrape cells free of tissue.Injecting saline into the area followed by application of a vacuumwithdraws the water and scraped cells from the patient.

U.S. Pat. No. 8,323,181 to Mukherjee describes an endoscope with aninsertion end that is about 1 to 2 mm in outer diameter. FIG. 5 showsthe tip of the insertion end of the endoscope, which has a flexiblepolyamide sheath. Enclosed within the sheath are an image-bundle focuslens, two laser-focus lenses, and optical fiber bundles used forillumination.

U.S. Pat. No. 8,858,425 to Farr describes an endoscope with removable,pluggable, and disposable optoelectronic modules. FIG. 7b shows asurgical tool 750 that can be inserted through the disposable cannula700 after the distal end 702 has been inserted inside the body. Thatdistal end 702 is made flexible so that, after insertion into thepatient, the entire distal tip 702 of the cannula can be expandedradially.

SUMMARY OF THE INVENTION

This is a general summary of the described technology commensurate inscope with the original claims. This technology overcomes disadvantagesof the previously known operative endoscopes, and provides a single-useor disposable, low-cost, electronic endoscope with a variable profiledistal tip. The technology encompasses various forms similar to anddifferent from the specific modes for implementing the inventions (alsocalled “embodiments”) described below. These described endoscopes areintended to provide a brief summary of some possible forms of thetechnology, and are not intended as a comprehensive disclosure of thefull scope or all of the features of the described technology and do notlimit the scope of the attached claims.

In one aspect, an electronic endoscope has a hub. A shaft extends fromthe hub. An expandable distal tip extends from the shaft. An imagesensor within the distal tip has a field of view external from theendoscope. A light source within the distal tip emits light within theimage sensor's field of view.

Tools can be passed from the hub, along the shaft within a workingchannel, and to the distal tip. A variable profile working channel atthe distal tip allows one or more tools to pass the image sensor andinto its field of view without increasing the overall size of theendoscope at the proximal shaft. The working channel changes from arelatively compact, generally noncircular cross-sectional shape to adifferent and enlarged cross-sectional shape. This shape changeaccommodates tools passing through the working channel, but also allowsthe endoscope to have a relatively low profile when first inserted intothe patient.

In another aspect, a single-use endoscope with a distal tip has a hubportion enclosing a light source and an insertion portion (that portioncapable of being inserted into the patient's body) extending from thehub portion. The insertion portion includes an expandable outer sheathat the distal tip of the endoscope. A light transmission system withinthe insertion portion conveys light from the light source and projectsthat light from the distal tip and onto a subject to be illuminated. Animage sensor, located approximately at the center of the distal tip,picks up an image of the illuminated subject.

A variable profile working channel extends from the hub portion to thedistal tip of the endoscope. A low-profile or reduced-profileconfiguration of the working channel fits within at least a portion ofspace defined between the image sensor and the expandable outer sheath.An enlarged-profile configuration has a cross-sectional shape sufficientto allow tools to pass the image sensor and to extend out from theendoscope's distal tip. When the working channel is in theenlarged-profile configuration, the expandable outer sheath has agenerally noncircular shape at the distal tip.

In a further aspect, an endoscope has a proximal end, a distal end, anda field of view at its distal end. A hub is at or near the proximal end.An insertion portion extends from the hub towards the distal end. Anexpandable distal tip extends from the insertion portion to the distalend and has a sensor. The sensor picks up an image within the field ofview. A working channel, a flushing lumen and a light-guide extendwithin the insertion portion from the hub to the distal end. At a pointalong the insertion portion, the endoscope has a cross-section with theflushing lumen, the light-guide, a generally circular cross-section ofthe working channel and a cable extending from the sensor to the hub.

The cross-section differs at another point along the distal tip. Thissecond cross-section has the sensor, the working channel, the flushinglumen and the light-guide. Both the working channel and the flushinglumen in this second cross-section have independently variable profiles.Each transforms from a generally noncircular, low-profile configurationto an enlarged-profile configuration. The enlarged-profile configurationallows one or more tools to pass through the working channel or permitsliquid to travel through the flushing lumen.

These endoscopes are capable of many variations. For example, the ratioof the length of the endoscope portion with the expandable orelastomeric working channel (1) to the outer diameter of the insertionportion (D) ranges from about 5:1 to about 1:1, and preferably is lessthan about 4:1, and most preferably less than about 2:1.

In at least some of the disclosed endoscopes, the expandable workingchannel assumes the enlarged-profile without moving the image sensorrelative to the light transmission system. For example, the expandabledistal tip can have an elastomeric sheath, which assumes a generallynoncircular cross-sectional shape when either the working channel or theflushing lumen is enlarged. In other disclosed endoscopes, the cameramoves slightly in one direction while the tip expands to allow a tool topass. Once the tool emerges and expansion is done, the camera can berepositioned. Having passed the camera, the tool can be pushed forwardor back with a range of motion that does not cause further cameramovement.

The expandable outer sheath, the flushing lumen and the variable profileworking channel can be made from various sterilizable, biocompatiblepolymeric materials. Each can be made from materials havingbiocompatible elastomeric tubing, which can be the same materials ordifferent materials. In addition, the flushing lumen and the variableprofile working channel can also be made from biocompatiblenon-elastomeric materials. The enlarged working channel is capable ofaccommodating passage of a tool having a circular cross-sectional shapewith a diameter equal to at least 50% of the outer diameter of theinsertion portion (D), preferably equal to at least 60% of D, and mostpreferably equal to at least 95% of D. When either the flushing lumen orthe working channel is enlarged, the outer sheath assumes a generallynoncircular cross-sectional shape.

The described electronic endoscopes are useful for various operative ortherapeutic procedures (e.g., arthroscopy, gall stone intervention,gynecologic endoscopy, kidney stone intervention, otolaryngologicendoscopy, and urologic endoscopy). Such disposable endoscopes do notneed re-sterilization, and can provide good visualization in arelatively small package, because the portion of the endoscope insertedinto the patient has an outer diameter of about 2 mm or less. Thisfacilitates therapeutic endoscopic use by general practice doctors intheir offices on an outpatient basis and avoids delays and costsassociated with scheduling procedures to occur in hospital operatingrooms.

Methods of assembling and using these endoscopes also are provided.

The technology has been briefly described thus far. This Summaryintroduces select concepts in a simplified form, which are furtherdescribed throughout this application, including in the DetailedDescription of the Preferred Embodiments. This Summary is neitherintended to identify key or essential features of the claimed subjectmatter, nor intended to be in any way limiting of the scope of theclaims attached hereto. The features mentioned above and those yet to beexplained below can be used not just in the stated combinations, butalso in other combinations, or alone, without departing from the scopeof this application. In addition to the illustrative aspects,embodiments, and features described above, a more complete understandingwill be afforded to those skilled in the art, as well as a realizationof these and other objects, features and advantages of the describedtechnology by consideration of the following text and the accompanyingillustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the described technology and otherwise clarify the aboveand other features and advantages of the technology, descriptions thatare more particular are provided below by reference to specificembodiments illustrated in the accompanying illustrative drawings. Thesedrawings depict selected modes of the described technology and are notto be considered limiting of its scope. The technology will be describedand explained with additional specificity and detail through the use ofthese drawings, in which like reference numerals refer to like partsthroughout, and in which:

FIG. 1 is a schematic view of an illustrative endoscope constructed inaccordance with the principles outlined in this application;

FIG. 2a is a perspective view of the expandable tip in the non-expandedconfiguration of the endoscope of FIG. 1;

FIG. 2b is a cross-sectional view of the expandable tip of FIG. 1 takenalong a section of FIG. 2 a;

FIG. 2c is a perspective view of the expandable tip in the non-expandedconfiguration of an endoscope with a non-circular camera;

FIG. 3 is a view of the non-expanded tip components of the endoscope ofFIGS. 2a and 2b underneath the outer cover sheaths;

FIG. 4 is a view of the expandable tip in an expanded configuration ofthe endoscope of FIG. 1;

FIG. 5 is a close-up view of the coupling hub of FIG. 1 with the distalhub enclosure removed;

FIG. 6 is a view of components inside the coupling hub of FIG. 1 withthe full enclosure removed;

FIG. 7 is a view of the PCA (Printed Circuit Assembly) board inside thecoupling hub of FIG. 1; and

FIG. 8 is a schematic view of an endoscope illumination system.

The provided drawings are illustrative and this technology is notlimited to the precise arrangements shown. The described technology canbe carried out in a variety of other ways, including those not depictedin the drawings. The drawings and angles of the disclosure are notalways to scale so as to clearly portray the attributes of thetechnology, are intended to depict typical aspects of the disclosure,and should not be considered as limiting the breadth, scope orapplicability of the described technology. Additional features andadvantages of the described technology are set forth in, and will beapparent from, the following Detailed Description of the PreferredEmbodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Various exemplary aspects of the described technology are illustrated inthe Figures and discussed below, which are presented to enable themanufacture and use of various aspects and examples of that technology.Descriptions of specific materials, techniques, and applications areprovided as examples. No limitation on the scope of the technology andof the claims that follow is to be imputed from the drawings, theexamples, or the discussion below.

This application provides an electronic endoscope with a variableprofile tip, in particular a single-use or disposable, low-cost,electronic endoscope with a variable profile working channel.

In one endoscope, the electronic endoscope has a hub, which remainsoutside the patient's body. The hub is used by the doctor to manipulatethe endoscope. An elongated, flexible shaft extends from that hub. Thisis the portion of the endoscope, that can be inserted into the patient'sbody. An expandable tip extends from the end of the shaft that isfarthest away from the hub. This is the distal tip. This expandabledistal tip has sensors that allow the doctor to see inside the patient'sbody and a working channel, which allows the doctor to treat or operateon nearby structures. In particular, a complementary metal oxidesemiconductor (CMOS) image sensor is positioned within the distal tipand has a field of view external from the endoscope, although othersensors can also be used. One or more illuminating fibers within thedistal tip emit light within the image sensor's field of view.

The distal tip has a variable profile working channel. The workingchannel permits one or more tools (e.g., ablation devices, cannulas,dissectors, electrodes, forceps, graspers, knot pushers, laser fibers,needle holders, suction and irrigation instruments, trocars, and othertools) to be passed within the endoscope from the hub to the imagesensor's forward field of view. The variable profile working channel canchange shape to allow the tools to pass alongside the image sensor. Forexample, the expandable working channel can change from a generallynoncircular cross-sectional shape to a different and enlargedcross-sectional shape which permits tools to pass.

Another endoscope has a hub that encloses a light source. The doctoruses the hub to manipulate the endoscope. An insertion portion extendsfrom the hub. At the distal tip of the endoscope (furthest from thehub), the insertion portion has an expandable outer sheath. A lighttransmission system conveys light from the hub and onto a subject to beilluminated beyond the distal tip. An image sensor is positioned atapproximately the center of the endoscope's distal tip. The sensor picksup an image of the illuminated subject.

A variable profile working channel extends from the hub to the distaltip of the endoscope. The working channel is positioned inside theexpandable outer sheath. A low-profile configuration of the workingchannel fits within a space defined between the image sensor and theexpandable outer sheath. An enlarged-profile configuration of theworking channel permits tools to travel past the image sensor and out ofthe distal tip. When the working channel is in the enlarged-profileconfiguration, the expandable outer sheath has a generally noncircularshape at the distal tip.

A further endoscope has a proximal end closest the doctor, a distal endat the opposite end and a field of view at that distal end. The hub isat the proximal end. The portion of the endoscope which extends from thehub towards the distal end can be termed the “insertion portion.”Depending on the doctor's needs, some or the entire insertion portioncan be inserted into the patient. The hub remains outside the patient.

An expandable distal tip extends from the insertion portion to thedistal end and has a sensor configured to pick up an image within thefield of view. A working channel, a flushing lumen, and a light-guide(e.g., one or more optical fibers) extend within the insertion portionfrom the hub to the distal end. At a point along the insertion portion,the endoscope has a cross-section, which includes the flushing lumen,the light-guide, a generally circular cross-section of the workingchannel, and a cable extending from the sensor to the hub.

At a different point along the distal tip, the endoscope has a differentcross-section. That different cross-section has the image sensor, theworking channel, the flushing lumen, and the light-guide. Both theworking channel and the flushing lumen are capable of changing theirprofiles, and are capable of doing so independently of one another. Eachcan assume a generally noncircular, low-profile configuration. Each canalso assume an enlarged-profile to accommodate a tool passing throughthe working channel or to accommodate liquid passing through theflushing lumen.

Each of the endoscopes described briefly above has an expandable distaltip, a variable profile working channel and, optionally, an expandableflushing lumen. The materials from which these three structures are madecan be the same or different. Biocompatible elastomeric material can beused to make all three structures (e.g., silicone rubber, thermoplasticelastomer (TPE)). TPEs include copolyester elastomers (e.g., ARNITEL®from DSM), polyether block amide (e.g., PEBAX® from Arkema), polyetherpolyester block copolymers (e.g., HYTREL® from Du Pont), polyolefinelastomers (e.g., ENGAGE® from Dow Chemical), polyurethane elastomer(e.g., PELLETHANE® from Dow Chemical), styrene block copolymers (e.g.,EVOPRENE® from AlphaGary), styrene-butadiene block copolymers (e.g.,STYROFLEX® from BASF), styrene-ethylene-butylene-styrene blockcopolymers (e.g., KRATON® from Kraton Polymers), and thermoplasticvulcanizates (e.g., SANTOPRENE® and GEOLAST® from ExxonMobil).

The working channel and the optional flushing lumen also can be madefrom non-elastomeric materials, which can change from a low-profileconfiguration to an enlarged-profile configuration (e.g.,poly(ethylene-vinyl acetate) (PEVA), polyimide, polytetrafluoroethylene(PTFE), or polyvinyl chloride (PVC)). Relatively rigid tools passthrough the working channel, which can benefit from a more durable,rugged polymeric material, while the distal tip needs to accommodate theenlarged working channel and/or enlarged flushing lumen.

Referring now to FIG. 1, an endoscope 1 has an expandable tip 2, a shaft3, a coupling hub 4, a connector assembly 5, and a USB connector 13. Theendoscope 1 shown has an overall working length (combined length of theshaft 3 and the distal tip 2) of between 5 cm and 200 cm, preferablybetween to cm and 100 cm, and most preferably between 12 cm and 600 cm.The working length should be sufficient to allow the tip of theendoscope 1 to be positioned within the patient's body so that therelevant anatomy can be seen, while maintaining the coupling hub 4outside the patient's body.

The shaft 3 extends from the distal tip 2 to the coupling hub 4. Theshaft 3 transmits torque (rotation) applied about a longitudinal axis ofthe shaft 3. Torque applied to the proximal end of the shaft istransferred along the length of the shaft 3 and to the distal tip 2. Insome endoscopes, the shaft 3 is flexible and can be bent about atransverse axis of the shaft in a relatively small bend radius. Thisallows the endoscope to be maneuvered around anatomical structuresduring medical procedures. However, in other applications, some or theentire shaft 3 is rigid or semi-rigid.

The shaft 3 can be made from any biocompatible material with appropriatestrength characteristics (e.g., providing flexibility and strength intension and compression, as well as appropriate torque transfer from theproximal to the distal end). Materials from which the shaft 3 can bemade include biocompatible polyamides, polyesters,polyetheretherketones, polyetherurethanes, polyimides,polytetrafluoroethylene, and polyurethane epoxies. To provide additionalstrength or rigidity, reinforcing materials can be incorporated into theshaft 3. Such reinforcing materials include copper alloys, nickel alloys(e.g., Nitinol), stainless steel, and high modulus plastics such aspolyimides.

The coupling hub 4 contains one or more connectors 8, 9, 10 for tools,flushing fluid, and a stylet, as well as optional electronics. Thecoupling hub 4 has a size and shape which accommodates these components.Electronics within the coupling hub 4 include a PCA with circuitry tooperate the endoscope and a camera signal transmission system that arediscussed below. Alternatively, the PCA can function as aninterconnection to external control circuitry outside of the endoscope.If electronics internal to the hub 4 are not otherwise desired, the hub4 can be quite small and can serve as a connection joint between theother tubes, wires, and optical fibers.

The hub 4 is made of a biocompatible plastic, such as polycarbonate,acrylic, acrylonitrile butadiene styrene (ABS), cast epoxy, andthermoset plastics. Formed metal housings using biocompatible materials,such as several grades of stainless steel or titanium, are alsopossible.

The coupling hub 4 has a distal portion 18 and proximal portion 19. Thecoupling hub 4 includes one or more ports or connectors 8, 9, 10, andstrain relief features 11, 12. These connectors 8, 9, 10 include sealsto provide fluid tight seal between coupling hub 4 and the connectors 8,9, 10 (e.g., a LUER-LOK® lock component).

The connectors 8, 9, 10 attach firmly to the coupling hub 4 and allowdoctors to introduce tools and fluids at the hub 4 that can be used atthe distal tip 2 of the endoscope. This can be achieved by gluing,heat-welding, potting with thermoset plastic or epoxy, RF welding,screwing them on with a threaded connection, solvent bonding, ultrasonicwelding, or combinations of these processes. Any or all of these threeconnectors 8, 9, 10 can be attached to a flexible tube, which enters thehub 4.

The flushing channel connector 8 allows fluid to be introduced at thehub 4, which can travel through the flushing lumen 24. The styletchannel connector 9 allows for a stylet (not shown) to be inserted atthe hub 4 and into the stylet channel 27. The stylet is intended toinfluence the shape of the endoscope's flexible shaft 3. For example, amalleable and resilient wire made of materials such as 300-seriesstainless steel can be bent into a desired curvature or angle, andinserted through the stylet channel causing the flexible endoscope toconform to such curvature or angle. The working channel connector 10allows tools to be passed from the hub 4 through the working channel 28,within the shaft 3, and down to the working channel portion 23 withinthe distal tip 2.

Although the endoscope shown has a single variable profile workingchannel, it is contemplated that more than one working channel can beincluded. When multiple working channels are employed, they may be thesame size or different sizes. Some or all of the working channels canhave the variable profile feature. For example, a 5 mm endoscope couldhave two 1.2 mm working channels, both of which have the variableprofile feature.

Similarly, FIG. 1 shows three connectors 8, 9, 10 for the flushinglumen, stylet, and working channel, respectively. It is contemplatedthat as few as one connector could be used, or as many connectors asneeded for the flushing lumen, stylet, and working channel features ofthe particular endoscope. For example, an endoscope with two workingchannels, a stylet, and a flushing lumen could have four separateconnectors.

The electrical cable 5 and USB connector 13 provide an interface betweencircuitry within the coupling hub 4 and external devices. In FIG. 1, asingle cable 5 extends from the coupling hub 4 to the USB connector 13.This cable 5 has conductors for powering a light source within thecoupling hub 4 and has contacts for transmitting signals outputted bythe camera 22 to the USB connector 13. Multiple cables can be used with,for example, a first cable 5 conducting power to a light emitting diode(LED) light source in the coupling hub 4, and a separate second cable(not shown) transmitting signals receives from the camera 22.

The USB connector 13 connects to external control/display devices orinto an electronic interface box, which translates the USB signals intothose used by the external control or display devices. The USB connector13 also provides power for the electronic endoscope. Although a USBconnector is shown in FIG. 1, other wired connections (e.g., HDMI) andwireless connections (e.g., Bluetooth, WiFi) are also possible asdiscussed below.

The coupling hub 4 undergoes various forces during use, includingbending forces. Strain relief features 11, 12 protect the hub 4 and itscomponents from these forces. For example, FIG. 1 shows a distal strainrelief 11 and a proximal strain relief 12. Strain relief features 11, 12can be made from various materials. These include relatively hardinjection molded thermoplastics (e.g., acrylonitrile butadiene styrene(ABS)), or more flexible materials such the TPEs previously identified.When a TPE is used, it preferably has a higher durometer value than theexpandable tip components.

FIGS. 2a and 2b show the distal end of the endoscope 1 in bothperspective and cross-sectional views. In FIG. 2a , the expandable tip 2has an expandable outer cover 21. At the distal end, the structurewithin the expandable tip 2 is shown, and includes a variable profileworking channel 23, an expandable flushing channel 24, threeillumination fibers 25, and a camera 22. The distal tip 2 is long enoughto house the camera 22. For example, the distal tip 2 has a length fromthe end of the shaft 3 to the distal most part of the endoscope ofbetween 3 mm and 50 mm, preferably between 7 mm and 15 mm, and mostpreferably between 8 mm and to mm.

The distal tip 2 can enlarge and contract. In a low-profile state, thedistal tip 2 has a reduced cross-sectional area with an outer diameterof between about 1.5 mm and 20 mm, preferably between about 1.5 mm and 5mm, and most preferably between about 1.5 mm and about 2.0 mm. In anenlarged-profile or expanded state, the distal tip 2 has an enlargedcross-sectional area that will accommodate passage of one or more toolsthrough the working channel. For example, the enlarged-profileaccommodates passage of a tool having a circular cross-sectional shapewith a diameter of between 1.8 mm and 20 mm, preferably between 2 mm and5 mm, and most preferably between 1 mm and 2 mm. The profile changeallows tools to pass the camera 22, and ultimately to exit the distaltip of the endoscope.

The illumination fibers 25 are depicted as three flexible fiber-opticlight-guides. These fibers 25 carry light from a light source in thecoupling hub 4 to the distal tip 2 of the endoscope, illuminating afield of view. Although three fibers 25 are shown in FIG. 2A, as few asone fiber can be used or as many fibers as can fit within the allowablespace so long as they provide sufficient light for camera 22.Illumination fibers 25 can be made of glass, PMMA or other lighttransmitting materials. Combinations of different sized fibers 25 can beused, as long as they fit within the cross-sectional area of the distaltip 2 in its low-profile configuration and provide sufficientillumination intensity.

The camera 22 and illumination fibers 25 are positioned so the area tobe imaged is sufficiently illuminated. In the configuration shown, thecamera 22 can be approximately in the center of the distal tip 2, withthe working channel 23, the flushing lumen 24 and the illuminationfibers 25 angularly distributed around the circumference (e.g., theworking channel 23 separated by about 120° from the flushing lumen 24and by an equal amount from the illumination fibers 25). However,various locations of the working channel 23 and flushing channel 24relative to each other and relative to the camera 22 or the illuminationfibers 25 are possible.

The outer cover 21, the working channel 23, and the flushing channel 24are made of sterilizable polymeric materials. Within at least theexpandable tip portions, these structures are configured so that theycan change shape or expand. Each of these structures can be made fromthe same material, or the materials can be different. For example, eachcan be constructed of biocompatible elastomeric tubing (e.g., latexrubber, silicone rubber, or various USP Class 6 compatible TPEs).Exemplary TPEs are mentioned above.

In a single-use endoscope, sterilization by the original manufacturercan be done in bulk (e.g., using ethylene oxide gas, gamma radiation,steam). A single-use device can have tubing connections that buttagainst one another but still allow a small crack, gap, or void at thejoint. Materials suitable for the bulk sterilization, such as byethylene oxide gas, can also be used to construct the endoscope withoutconcern for the materials having to be compatible with multiple exposureto sterilization chemicals such as glutaraldehyde.

Coatings (not shown) can be applied to the outside of the endoscope. Forexample, such coatings could provide anti-bacterial or anti-microbialproperties (e.g., copper ions, silver ions). Coatings can also be usedto allow doctors to detect certain conditions. For example, specialpeptides and other formulations can be applied that detect presence ofbacterial contamination or biomarkers of other sorts.

To seal the distal tip of the endoscope, a UV-cured adhesive pottingcompound is applied at the distal tip and flows between the components,while it is viscous. Excess potting compound is removed and UV lightapplied to cure or harden the material. Other materials can also beused, such as 2-part epoxies. Application of the potting compounds maybe limited to areas that do not interfere with the expandable distal tipsections (e.g., by fixtures that limit the distribution area of thecompound), and/or use materials that do not bond to those expandablesections.

The working channel 23 has a low-profile configuration. For example, thelow-profile working channel 23 of a 2 mm endoscope can have a 0.5 mmdiameter within the shaft 3 and then assumes a more compactconfiguration within the distal tip 2 so that it fits the space betweenthe expandable outer cover 21 and the camera 22. In FIG. 2a , thelow-profile working channel 23 has a generally lunate cross-sectionalshape. The ends of the lunate cross-sectional shape can be rounded (asin FIG. 2A), or bent more sharply. Other shapes are possible, includingcircular, reniform, oblong, oval, etc.

The working channel 23 also has an enlarged-profile configuration toallow tools to pass the camera 22. For example, the enlarged-profileworking channel 23 of 2 mm endoscope is large enough to allow tools withan outer diameter of approximately 1.2 mm to pass through it.

The camera 22 is a CMOS color camera, which is biocompatible andwaterproof. Preferably, the camera provides a field of view externalfrom the endoscope. A forward field of view would look beyond the distaltip of the endoscope. However, the field of view can also be at an angleexternal from the endoscope (e.g., an off-angle-looking endoscope suchas 30°). The CMOS image sensor includes a multi-element lens assembly orgradient refractive index (GRIN) lens providing a field of view of30-180°, preferably of 50-130°, and most preferably 60-120°. Theeffective image resolution preferably is at least 10,000 pixels, morepreferably at least 40,000 pixels, and most preferably at least 60,000pixels, although image resolutions of 1 megapixel or greater arepossible. Other sensors can be used instead of or in conjunction withthe CMOS device so long as they provide sufficient image resolution. Forexample, a charge-coupled device (CCD) could be used.

Optionally, an optical prism can be added to modify the particularangular view of the image sensor. The prism has a reflective surfacethat “tilts” the viewing cone of the image sensor by a predeterminedamount, such as 30°, 70°, etc. The prism may be made of glass or anyclear polymer, such as acrylic or polycarbonate. The prism could bebonded using optically-clear epoxy to the flat distal surface of thecamera. More preferably, the prism could replace the final camera lensin the original manufacture of the device.

The camera sensor can be further affixed to the structure of theendoscope. The camera sensor can be affixed directly to the light guideto provide additional support. The camera cable can be adhered to thesheath cover, the working channel, or both. For example, the cameracable can be bonded to the inside of the sheath cover, just proximal tothe expandable distal tip section. These further connections provideadded stiffness.

The cross-sectional view of FIG. 2b is along section A-A of FIG. 2a ,and passes through the elongated shaft 3. A flexible, braided sheathcover 26 is made from a stainless steel reinforced polyimide material,although other materials can be used.

The braided sheath cover 26 contains five structures. The workingchannel 28 in this section is a flexible tube with a generally circularcross-sectional shape. The working channel 28 can be constructed fromany sterilizable polymeric material than can be affixed to the variableprofile working channel 23 shown in FIGS. 1 and 2 a, or working channel28 and variable profile working channel 23 can made from the same lengthof tubing. The material of working channel 28 can be the same materialas that of variable profile working channel portion 23, or they can bemade from different materials. For example, the working channel withinthe shaft 3 can be made from non-elastomeric polymeric materials (e.g.,poly(ethylene-vinyl acetate) (PEVA), polyimide, polytetrafluoroethylene(PTFE), polyvinyl chloride (PVC)) or from biocompatible elastomerictubing (e.g., latex rubber, silicone rubber, or various USP Class 6compatible TPEs).

Flushing fluid passes through the flushing channel 24. The flushingchannel 24 can have any cross-sectional shape within the shaft 3 so longas sufficient fluid can be passed. The flushing channel 24 shown in FIG.3 is made from a single length of elastomeric tubing. Alternatively, theproximal portion of flushing channel 24 within the shaft 3 can be madefrom non-elastomeric material (e.g., a polyimide tube) and coupled to anelastomeric tip section. Suitable elastomeric materials for the flushingchannel 24 are identified above.

A stylet channel 27 allows introduction into the endoscope of a stylet(not shown), which is a slender probe, typically made from a metal. Whenthe stylet is introduced, it provides additional stiffness. This canfacilitate proper positioning of the endoscope's distal tip within thepatient. In addition, the stylet can impart a particular shape to theendoscope (e.g., a particular curve or bend). The stylet channel 27should resist puncture by the stylet tip. Reinforcement is optional.This stylet channel 27 is made from various polymeric tubing materials,such as PEVA, polyimide, PTFE, or PVC. The stylet channel 27 is shown tohave a circular profile, but can have any profile that allows the styletto pass through it.

Also, a camera cable 29 extends from the camera 22 (shown in FIG. 2a )to the coupling hub 4 (shown in FIG. 1). The camera cable can be asimple signal conducting wire (e.g., a 24 AWG gauge copper wire with adiameter of about 0.52 mm), or a ribbon cable with several insulatedconductors. Exemplary conductor compositions include copper, copperalloys, MP35N, DFT, platinum, platinum/iridium, tungsten, gold, andstainless steel. The conductors can be bare, tinned, silver-plated, orgold-plated. Various insulating materials can be used, includingfluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), andpolytetrafluoroethylene (PTFE). For example, the ribbon cable can beconstructed with four conductors: (1) a ground, (2) a serial data line,(3) a serial clock line, and (4) a power line (e.g., using 41 AWG silverplated copper conductors).

FIG. 2c shows the distal end of another endoscope made with anon-circular camera 22 that is radially offset from the center of theendoscope. The working channel portion 23 within the distal tip 2 andthe flushing lumen 24 are adjacent the camera 22 and the elastomeric tipcover 21.

To allow the inner structures to be seen, FIG. 3 shows the endoscope ofFIG. 2a without outer covers 21 and 26. The coupling sleeve 31 is athin-wall cylindrical material that joins the elastomeric tip cover 21and the flexible braided sheath 26. Coupling sleeve 31 depicted in FIG.3 can be made from polyimide, stainless steel, polyurethane or otherthin-wall tubing. This coupling sleeve 31 is bonded to the insidesurfaces of the braided flexible sheath 26, and the elastomericexpandable tip cover 21. Joining can be by adhesive bonding, heatwelding, mechanical ring-clamping or solvent bonding, or other methodsfor durably bonding these components.

The stylet channel 27 is a thin-wall tubing similar to that describedpreviously for other working channels such as polyimide, PTFE, or othertubing, and which has a durable stop 33 at its distal tip, such as aplug of hard plastic such as acrylic, ABS, or other material bondable ormechanically securable to the stylet channel, which is intended toprevent the stylet from puncturing or damaging other components. Thetubing also can be crimped or folded over at the end to create a stop ifthe tip of the stylet is rounded. This can be in addition to the hardplastic plug or instead of it.

An optional deflector ramp 34 is also shown in FIG. 3. The deflectorramp provides an angled, relatively hard surface to guide the distal tipof the tool around the proximal edge of the camera and into the distaltip expansion area of the working channel. This deflector ramp can bemade of hard plastic such as acrylic or ABS, or from a thin stampedstainless steel metal piece, and may be curved to match the outsidediameter of the working channel shaft. As described above in connectionwith FIGS. 2a and 2b , the working channel has a generally circularcross-section 28 within the shaft 3 and a variable profile section 23within the distal tip 2. As a tool passes through the circularcross-section of the working channel shaft 28 to the variable profileworking channel 23, it moves around the camera 22 and exits the distaltip of the endoscope. The ramp 34 is affixed to the endoscope. Forexample, the ramp can be adhered to the proximal surface of the camera22, to the expandable work channel 23, to the sheath cover 26, or tocombinations of these structures. A UV-curable epoxy or other adhesivecan be used for this purpose. The ramp 34 defines an angle relative tothe longitudinal axis of the endoscope that can range from about 30° toabout 60°, and preferably ranges between 40° and 50°, and mostpreferably about 450. A ratio of the length of the ramp 34 to theoverall outer diameter of the endoscope at the distal tip is less thanabout 1:2, preferably is less than about 1:3, and most preferably isless than about 1:5.

A coupling sleeve 35 can be used when the circular cross-section workingchannel shaft 28 and the expandable working channel 23 are made fromdifferent materials or different sections of tubing that are affixedtogether. If these are made using a single length of tubing, couplingsleeve 35 can be omitted. Unlike the outer sheath coupling sleeve 31(which fits inside the outer cover of the expandable tip cover 21) andthe flexible, braided sheath cover 26 (which allows the endoscope tomaintain an even outer diameter), working channel coupling sleeve 35fits on the outside of a joint between the circular cross-sectionworking channel shaft 28 and the expandable working channel 23 topreserve a consistent inner diameter for tool insertion and removal. Thecoupling sleeve 35 can be a short piece of thin-wall polymeric tubing(e.g., a 4-5 mm of 0.0.254 mm wall thickness polyimide tubing, which isobtainable from Putnam Plastics or Vention Medical).

The variable profile distal tip allows the doctor to insert theendoscope through a minimal incision or puncture size (e.g., for a 12gauge needle) while it is in a low-profile configuration. Once theendoscope is in the area to be treated, the tip section is enlarged.FIG. 4 illustrates the distal tip 2 in an enlarged-profileconfiguration.

Such a configuration is achieved, for example, by passing a full 1.0 mmdiameter tool through the working channel tip 23, and/or flushing fluid(0.9% saline in sterile water) through the flushing channel 24 at a ratesufficient to expand the flushing channel 24 at the distal tip 2.

FIGS. 5 and 6 show details of the coupling hub 4. In FIG. 5, the distalenclosure portion 6 is removed. The flushing channel tube 51 is attachedto flushing channel connector 8. The stylet channel tube 52 is attachedto the stylet channel connector 9. The working channel shaft 53 isattached to the working channel connector 10. On the proximal ends,tubes 51, 52, 53 attach to connectors, such as Luer or Luer lockconnectors. Solvent bonding, adhesive bonding, or press fit can be usedto make this connection.

In FIG. 6, the proximal hub enclosure 7 is removed to reveal the PCA 61,the proximal end of the camera cable 29, and the proximal end of theillumination fibers 25.

FIG. 7 is a close-up view of the PCA 61. Camera cable 29 connects to thePCA 61 using connector 72. LED 71 is an LED surface-mounted chip withthe proximal ends of the illumination fibers 25 placed flush against thelight emitting surface area of LED 71. However, non-LED illuminationsources can be used (e.g., halogen incandescent, xenon light, diodelasers) so long as the particular illumination chosen can be picked upby the camera or sensor. An epoxy provides a secure attachment, althoughother methods can be appropriate.

Mounting screws 73 attach the PCA 61 to studs molded into the proximalhub enclosure 7. Other PCA mounting techniques can be used, includingcapturing the PCA 61 between the proximal hub enclosure portion 19 andthe distal hub enclosure portion 6. Attachment of the two-hub enclosureportions 6, 7, the strain reliefs 11, 12 and, in turn, their attachmentsto the electronic cable 5, the coupling hub 4, and endoscope shaft 3 arewatertight. Such watertight connections can be achieved by a number ofmeans including flexible adhesive, solvent bonds, heat seals, rubbergrommets and other seals.

The PCA 61 circuitry controls illumination intensity of the light source71 and operates the camera 22. The PCA 61 circuits translate signals toand from an external control/display (not shown). These circuits convertsignals into the patterns, voltages, timing, etc., needed by, or sentfrom the camera 22 and used for the illumination source 71. Suchtranslation can include converting the signals into a Universal SerialBus (USB) standard. Multi-layer or stacked multi-layer circuits withembedded software (e.g., firmware) and Field Programmable Logic Arrays(FPGAs) translate and communicate the signals.

If wireless communication is desired (whether RF, Infrared or anothermethod of communication), the PCA 61 includes a wireless transceiver anda power source (e.g., battery). The battery powers the PCA 61 and theimage sensor 7. The wireless transceiver interfaces with externalcontrol and display devices. For example, the PCA 61 wirelesslytransmits image signals from the image sensor 7 to an external display.

Alternatively, signal translation can be accomplished externally of theendoscope. In that case, the PCA 61 functions as an interconnection androutes signals to a cable 5, which then connects to an externalcontrol/display unit (not shown).

FIG. 8 illustrates an illumination configuration for the electronicendoscope. Within the hub 4, numerous LEDs and illumination fibers orfiber bundles can be arranged to assure sufficient illuminationintensity to achieve the desired field of view and depth of field. LED82, if small enough, can be mounted adjacent to the camera 22 within theexpandable tip section 2. Illumination fibers 81 are routed from the LED82 to reach the outside of the camera 22 at the distal tip 2. Such anillumination subassembly can be rigid.

The illumination subassembly can be varied, so long as sufficientillumination intensity to achieve the desired field of view and depth offield. For example, a shaped light guide can be used to replace opticalillumination fibers, as long as the Numerical Aperture and illuminationfield pattern of the light emitted from the light guide is compatiblewith the field of view of the camera 22. The LED can be mounted withinthe shaft section 3 or can be exterior to the endoscope, instead ofwithin the hub enclosure 4.

The following Examples are presented to illustrate the describedtechnology, and are not intended to limit the attached claims in anyway.

Example 1

A 2 mm endoscope with expandable working channel and an LED light sourcein the hub similar to that shown in FIG. 1 is formed as described below.Two injection-molded ABS pieces 6, 7 (available from Dow Chemical) formthe hub enclosure.

Insert cable assembly 5 with USB connector 13 (available from MolexConnector Corp.) into a strain relief tube 12 and then into a proximalopening in the proximal hub enclosure 7. The strain relief tube 12 is aninjection molded component made from Shore A 60 TPE. The cable assembly5 is electrically connected to a printed circuit assembly (PCA) 61.

PCA 61 is a small, multi-layer printed circuit board with surface mountintegrated circuits to convert USB signals and communications to/fromthe camera into the signal levels and timing required by the cameraspecifications. The PCA 61 is affixed to the proximal hub enclosure 7using four screws 73. See FIG. 7.

The proximal hub enclosure has an opening for the working channel. Aworking channel connector 10 provides a fluid tight seal between theproximal hub enclosure 7 and the working channel. Insert connector 10 (acommercially available LUER-LOK® lock component) into the proximal hubenclosure 7.

The sheath cover 26 is a 29.2 cm length of braided stainless steelreinforced polyimide tubing (Putnam Plastics catalog number 142-0045;1.88 mm OD, 1.689 mm ID).

The distal strain relief tube 11 is an injection molded component madeof Shore A 60 TPE. Insert this tube through an opening in hub enclosure6. Slide the sheath cover 26 through the distal strain relief 11 foraccess to the interior of the hub enclosure 6. Solvent bond withcyclohexanone to affix the sheath cover 26 to distal strain relief tube11.

The outer sheath 21/26 is formed from the polyimide and silicone tubingusing a manufacturing mandrel. Slide thin-walled polyimide coupling tube31 with an outer diameter (OD) of about 1.689 mm onto the properly sizedmandrel. Then, slide an 8 mm length of silicone rubber tubing with an IDof about 1.689 mm (which will form the expandable distal tip cover 21)and the sheath/cover assembly 11, 26 onto the mandrel from opposite endsuntil they butt up against one another over the polyimide coupling tube31. Bond the silicone rubber tube 21, the polyimide coupling tube 31 andthe stainless steel reinforced polyimide tube 26 with cyclohexanone tocreate a durable joint.

The working channel is also formed using a mandrel. Slide a 29.2 cmlength of polyimide tubing 28 (Vention Medical catalog number 141-0083;0.0505 in OD×0.048 in ID) onto a mandrel of appropriate diameter. Slidean 8 mm length of USP Class 6 TPE tubing (KRATON from Kraton Polymers)onto the mandrel so it butts up against the polyimide tubing 28. Coverthe resulting joint with a thin-walled polyimide coupling sleeve 35(from Vention Medical). Join these components together with alow-viscosity ultraviolet light cure adhesive (208-CTH-F flexible, waterresistant catheter bonding adhesive available from Dymax Corp.).Together the working channel assembly 23/28/35 is 30 cm long.

Slide the working channel assembly 23/28/35 into the outer sheath andpreviously constructed cover assembly. Connect a proximal end of theworking channel assembly 23/28/35 to the working channel connector 10.Cyclohexanone solvent bonds the proximal end of the working channel tothe connector 10.

Bond an acrylonitrile butadiene styrene (ABS) ramp 34 to the outside ofthe working channel expandable tip with cyclohexanone. Approximately themid-point of the ramp 34 is at the rear edge of the camera 22, and theramp provides a smooth angle for a tool to traverse into the expandabledistal tip area. The ramp 34 forms an angle of 45° with respect to thelongitudinal axis of the endoscope, and has a length of about 2-3 mmalong that longitudinal axis.

Then, attach camera 22 to PCA 61. The camera is a micro ScoutCam™ 1.2(Medigus, Ltd. of Omer, Israel). This camera 22 is cylindrical in shapeand measures 1.2 mm in diameter by 5 mm in length, and provides aneffective image resolution of about 44,880 pixels. Camera cable 29extends from camera 22, runs within the cover assembly but along theoutside of the assembled working channel, and connects to PCA 61 at thecamera connector 72. See FIG. 7. PCA 61 controls camera 22 and receivesimages from it.

Three optical illumination fibers 25 (outer diameter of 0.25 mm, fromLightHouse LEDs as catalog number 0.25 MMFIBERENDGLOW) also run withinthe cover assembly along the outside of the working channel assemblyuntil they are adjacent to the camera 22. Adhere proximal ends of theillumination fibers 25 onto the light source 71, a Luxeon® C power LED(available from the Philips Lumileds Lighting Company) with UV-curedadhesive (208-CTH-F adhesive available from Dymax Corp.).

Then, seal the tip and bond the components together with Dymax adhesive.

Slide the distal hub enclosure 6 over the cover/working channelassemblies. The distal and proximal hub enclosures 6, 7 snap-fittogether. Heat seal them together to obtain a liquid-tight seal.

This provides an endoscope with a 30 cm working length, a 2 mm OD, andvariable profile distal tip and working channel. Such an endoscope canbe used for a variety of endoscopic applications including arthroscopicjoint examination and surgery for hands, shoulders, knees, etc.

Example 2

An endoscope similar to that described in Example 1 is formed with avariable profile flushing lumen 24 in addition to the variable profileworking channel as illustrated in FIG. 2A. A 30 cm length of TPE tubing(Vention Medical PEBAX® tubing catalog number 115-1289; 0.0.279 mm ID,0.1143 mm wall thickness, 0.51 mm OD, Shore A 63) forms the flushinglumen 24. The process for making the endoscope is similar to Example 1.Differences are discussed below.

Place the PEBAX® tubing adjacent to the working channel assembly23/28/35, and push the proximal end of tubing over a barb fitting theLUER-LOK® lock connector 8. This secures the flushing lumen 24 to theproximal hub enclosure 7. Position the distal end of the flushing lumentubing 24 adjacent the camera 22 within the expandable tip beforesealing the tip.

Example 3

An endoscope similar to that described in Example 2 except the flushinglumen 24 is made from a non-expandable material. Instead of PEBAX®tubing, the flushing lumen 24 is made from polyimide tubing (VentionMedical catalog number 141-0023; 0.508 mm OD, 0.457 mm ID).

Even though the material itself is non-expandable, the flushing lumen ismanufactured to provide that feature. At the distal end, heat press an 8mm length of the polyimide tubing to form creases and a flattened end.This enables the polyimide tubing to curve around camera 22 inside theexpandable outer cover 21. Place a proximal end of the polyimide tubingover the barbed connector of the commercially available connector 8 (aLUER-LOK® component) and affix it with Methyl-Ethyl-Ketone solvent.

In use, the creased and flattened distal tip of the flushing lumen 24expands as fluid passes within the flushing lumen 24. This, in turn,expands the outer cover 21. See FIGS. 3 and 4.

Example 4

An endoscope similar to that described in Example 1 is configured forwireless communication with an external display and a control device(e.g., a PC or tablet computer). The PCA 61 has wireless transmittingand receiving components. Commonly available button-style batteries areincluded within the hub assembly to power PCA 61. An antenna wire isincluded and attached to the PCA 61. Connect a switch in series with thebattery. The batteries provide sufficient power to allow the endoscopesystem to function for several hours.

Example 5

An endoscope similar to that described in Example 1, except theexpandable working channel is a 30 cm length of non-reinforced polyimidetubing (Vention Medical catalog number 141-0083, 1.283 mm OD×1.219 mmID). As described in Example 3 above, heat press an 8 mm length of thepolyimide tubing at the distal end to form creases and a flattened end.This enables the polyimide tubing to curve around camera 22 inside theexpandable outer cover 21. When a tool or other item is forced throughthe working channel, the creased and flattened distal tip will expand,in-turn expanding the outer cover 21, to the extent needed to allow thetool or other item to pass through.

In addition, in this example the camera 22 is an Awaiba NanEye camera(available from AWAIBA Lda). This camera 22 measures 1.1 mm×1.1 mm×1.7mm long with a diagonal measurement of 1.41 mm, and provides aneffective image resolution of about 62,500 pixels. FIG. 2c shows across-sectional view of this endoscope at the distal tip.

Example 6

An endoscope similar to that described in Example 1 except that it hasan outer diameter of 1.7 mm.

The outer sheath 21/26 is formed from a 29.2 cm length of a braidedstainless steel reinforced polyimide tubing (1.72 mm OD, 1.57 mm ID,available from Vention Medical catalog 142-0042), an 8 mm length ofsilicone rubber tubing with an ID of about 1.689 mm, and a thin-walledpolyimide coupling tube 31 with an OD of about 1.689 mm

The working channel is formed from thin-wall polyurethane tubing(Vention Medical catalog number 115-0565; 1.346 mm OD, 0.089 mm wall,1.168 mm ID).

The camera is the NanEye camera described above in Example 5. Theillumination light guides (optical fibers) are 0.125 mm OD (0.1 mm corediameter, Edmund Optics stock #57-061) and eight total fibers are usedfor the illumination. The four-conductor cable from the NanEye camera 22is connected to PCA 61 for signal connection to a cable suitable forexternal use and possible signal processing circuits are included on PCA61 to convert the signals to USB standards or other desiredconfiguration. PCA 61 has memory containing calibration information forthe specific NanEye camera being used.

The foregoing detailed description contains discussion of various formsof practicing the technology, and includes many specifics for thepurpose of illustration. The technology is susceptible to manyvariations, modifications, replacements, and alternative forms based onthe disclosures and suggestions described in this application withoutdeparting from the spirit and scope of the claims. Examples are used toillustrate particular embodiments; however, the claims are not intendedto be limited to these examples, but rather include the full scope ofthe claims. Accordingly, the foregoing descriptions of the selectedembodiments and following examples are set forth without any loss ofgenerality to, and without imposing limitations upon, the describedtechnology.

Further, in the foregoing detailed description of the selectedembodiments, reference is made to the accompanying drawings that form apart hereof, and in which are shown by way of illustration specificembodiments in which the described technology can be practiced. Otherembodiments can be utilized and structural changes can be made withoutdeparting from the scope of the described technology. For instance,general principles and features illustrated or described as part of oneembodiment can be used in another embodiment to yield a still furtherembodiment without departing from the spirit and scope of the describedtechnology. Accordingly, the scope of the claims is not limited by theabove description. All changes, which come within the meaning and rangeof equivalency of the claims, are to be embraced within their scope.

What we claim is:
 1. An endoscope comprising: a hub; a shaft extendingfrom the hub, the shaft having an outer dimension; a distal tipextending from a distal portion of the shaft; an image sensor within thedistal tip, the image sensor having a field of view external to theendoscope; an illuminating element configured to emit light within thefield of view of the image sensor; a first working channel tube disposedwithin the shaft and extending continuously from a proximal end at thehub to a distal end within the distal tip, the first working channeltube comprising a first portion within the distal tip, wherein the firstportion of the first working channel tube is configured to expand to anenlarged configuration to accommodate passage of a first object, whereinthe distal tip has a dimension greater than the outer dimension, whenthe first portion of the first working channel tube has the enlargedconfiguration, and wherein the first working channel tube is configuredto accommodate passage of the first object through a proximal portion ofthe shaft while maintaining the outer dimension of the shaft; and asecond working channel tube disposed within the shaft generally parallelwith the first working channel tube and extending continuously from aproximal end at the hub to a distal end within the distal tip, thesecond working channel tube comprising a second portion within thedistal tip, wherein the second portion of the second working channeltube is adapted to expand to an enlarged configuration to accommodatepassage of a second object, wherein the distal tip has a dimensiongreater than the outer dimension when the second portion of the secondworking channel tube has the enlarged configuration, and wherein thesecond working channel tube is configured to accommodate passage of thesecond object through the proximal portion of the shaft whilemaintaining the outer dimension of the shaft; and wherein the imagesensor is located between the first working channel tube and the secondworking channel tube and the first working channel tube and the secondworking channel tube are separated by the image sensor, and expansion ofthe first portion of the first working channel tube to the enlargedconfiguration radially expands the distal tip in a first direction,expansion of the second portion of the second working channel tube tothe enlarged configuration radially expands the distal tip in a seconddirection, generally opposed to the first direction, the distal tiphaving a greater dimension when either or both of the first and secondworking channel tubes expand to their enlarged configuration such thatexpansion of the first and second portions cause corresponding expansionof the distal tip.
 2. The endoscope of claim 1, wherein the firstworking channel tube and the second working channel tube are angularlyseparated around a circumference of the distal tip by about 120°.
 3. Theendoscope of claim 1, wherein the first working channel tube and theilluminating element are angularly separated around a circumference ofthe distal tip by about 120°.
 4. The endoscope of claim 1, wherein theimage sensor comprises a circular cross-sectional shape.
 5. Theendoscope of claim 1, wherein the image sensor comprises a noncircularcross-sectional shape.
 6. The endoscope of claim 1, wherein theilluminating element comprises an illumination fiber.
 7. The endoscopeof claim 1, wherein the illuminating element is located at leastpartially within the distal tip.
 8. The endoscope of claim 1, furthercomprising an illumination source in communication with the illuminatingelement, wherein the illumination source is located in the hub.
 9. Theendoscope of claim 1, further comprising an illumination source incommunication with the illuminating element, wherein the illuminationsource is located in the distal tip.
 10. The endoscope of claim 1,wherein the first object comprises a tool.
 11. The endoscope of claim 1,wherein the first object comprises a fluid.
 12. The endoscope of claim1, wherein the first object comprises a first tool and the second objectcomprises a second tool.
 13. The endoscope of claim 1, wherein an outerdiameter of the distal tip has a reduced cross-sectional area with anouter diameter of between about 1.5 mm and 5 mm.
 14. The endoscope ofclaim 1, wherein the distal tip is further configured for positioningthe distal tip at a specified location within a patient.
 15. Theendoscope of claim 8, wherein the illumination source is selected fromthe group consisting of: an LED illumination source, a halogenillumination source, an incandescent illumination source, a xenon lightillumination source, and a diode laser illumination source.
 16. Theendoscope of claim 9, wherein the illumination source is selected fromthe group consisting of: an LED illumination source, a halogenillumination source, an incandescent illumination source, a xenon lightillumination source, and a diode laser illumination source.
 17. Theendoscope of claim 10, wherein the tool is selected from the groupconsisting of: an ablation device, a cannula, a dissector, an electrode,a forceps, a grasper, a knot pusher, a laser fiber, a needle holder, asuction device, an irrigation instrument, and a trocar.
 18. An endoscopecomprising: a hub; a shaft extending from the hub, the shaft having ashaft width; a distal tip extending from the shaft; an image sensorlocated at least partially within the distal tip, the image sensorhaving a field of view external to the endoscope; an illuminatingelement configured to emit light within the field of view of the imagesensor; a first channel tube extending continuously from the hub to thedistal tip, the first channel tube having a proximal portion located atleast partially within the shaft and a distal portion located at leastpartially within the distal tip, wherein the proximal portion of thefirst channel tube is configured to accommodate passage of a firstobject within the shaft width, wherein the distal portion of the firstchannel tube is configured to expand from a first width to a secondwidth to accommodate passage of the first object through the firstchannel tube, wherein the distal tip has a width greater than the shaftwidth when the first channel tube is expanded to the second width; and asecond channel tube extending continuously from the hub to the distaltip, the second channel tube having a proximal portion located at leastpartially within the shaft and a distal portion located at leastpartially within the distal tip, wherein the proximal portion of thesecond channel tube is configured to accommodate passage of a secondobject within the shaft width, wherein the distal portion of the secondchannel tube is configured to expand from a third width to a fourthwidth to accommodate passage of the second object through the secondchannel tube, wherein the width of the distal tip is greater than theshaft width when the second channel tube is expanded to the fourthwidth; wherein expansion of the first channel tube and the secondchannel tube cause corresponding expansion of the distal tip.
 19. Theendoscope of claim 18, wherein the distal portion of the first channeltube is configured to expand from a lunate cross-sectional shape havingthe first width to a rounded cross-sectional shape having the secondwidth.
 20. The endoscope of claim 19, wherein the distal portion of thesecond channel tube is configured to expand from a lunatecross-sectional shape having the third width to a roundedcross-sectional shape having the fourth width.